Method of manufacturing the optical apparatus

ABSTRACT

A method of manufacturing an optical apparatus is provided. The method includes arranging a photo device above a substrate with an adhesive located between the photo device and the substrate, forming a bonding member that bonds the substrate and the photo device by curing the adhesive, and arranging, above the photo device, a transparent plate and a sealing member. The sealing member covers the photo device and is located between the transparent plate and the substrate. An elastic modulus of the bonding member is 1 GPa or less.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to an optical apparatus and a method ofmanufacturing the same.

Description of the Related Art

Japanese Patent Laid-Open No. 9-129780 proposes a method ofmanufacturing an IC package (optical apparatus) in which a photo sensorIC chip is fixed on a printed board and covered with a transparentresin, and the transparent resin is covered with an opticallytransparent member such as a glass member.

SUMMARY OF THE INVENTION

In the manufacturing method of Japanese Patent Laid-Open No. 9-129780,the transparent plate such as a glass plate located on the photo sensormay warp due to a force generated by the substrate, transparent resin,or the like during the manufacture of the optical apparatus. Thiswarping degrades the performance of the optical apparatus. An aspect ofthe present invention provides a technique for suppressing warping thatoccurs in the transparent plate of an optical apparatus.

According to an aspect of the present invention, provided is a method ofmanufacturing an optical apparatus, comprising: arranging a photo deviceabove a substrate with an adhesive located between the photo device andthe substrate; forming a bonding member that bonds the substrate and thephoto device by curing the adhesive; and arranging, above the photodevice, a transparent plate and a sealing member, the sealing membercovering the photo device and located between the transparent plate andthe substrate, wherein an elastic modulus of the bonding member is 1 GPaor less.

According to another aspect of the present invention, provided is anoptical apparatus comprising: a substrate; a photo device fixed to thesubstrate by a bonding member; a transparent plate located above thephoto device; and a sealing member that is located between thetransparent plate and the substrate and covers the photo device, whereinan elastic modulus of the bonding member is 1 GPa or less.

Further features of the present invention will become apparent from thefollowing description of exemplary embodiments (with reference to theattached drawings).

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic sectional view for explaining an example of thearrangement of an optical apparatus according to some embodiments.

FIGS. 2A to 2F are schematic sectional views for explaining an exampleof a method of manufacturing the optical apparatus according to someembodiments.

FIGS. 3A and 3B are schematic sectional views for explaining warpingthat occurs in the optical apparatus according to some embodiments.

DESCRIPTION OF THE EMBODIMENTS

Preferred Embodiments of the Present Invention will now be describedwith reference to the accompanying drawings. The same reference numeralsdenote the same elements throughout various embodiments, and arepetitive description thereof will be omitted. The embodiments canappropriately be modified or combined.

The structure of an optical apparatus 100 according to some embodimentswill be described with reference to the schematic sectional view ofFIG. 1. The optical apparatus 100 includes components shown in FIG. 1.In the following description, the upper portion of the drawing will bereferred to as the upper side of each component, and the lower portionof the drawing will be referred to as the lower side of each. Theoptical apparatus 100 is mounted on, for example, an image capturingapparatus such as a camera. A photo device 110 is, for example, a photosensor that generates an electrical signal by photoelectric conversionbased on light that has entered the optical apparatus 100 and reached alight-receiving surface 111 of the photo device 110. The photo device110 can have any structure, for example, an existing structure, and adetailed description thereof will be omitted. The photo device 110 maybe, for example, an autofocus sensor that measures the distance to thelight source based on the positional relationship between photodiodeslocated at the focal points of light divided into two parts by spectaclelenses. Alternatively, the photo device 110 may be an image sensor thatgenerates image data using a plurality of pixels arranged on an array.The photo device 110 may be a display device.

The photo device 110 is fixed on the upper surface of a substrate 120 bya bonding member 130. For example, the bonding member 130 is a resin.For example, the bonding member 130 is formed by curing a liquidadhesive arranged between the photo device 110 and the substrate 120.The substrate 120 has terminals 121 extending through it. Each terminal121 includes an inner portion 121 a located on the upper surface of thesubstrate 120, an outer portion 121 b located on the lower surface ofthe substrate 120, and a connection portion 121 c located in a throughhole formed in the substrate 120 and connecting the inner portion 121 aand the outer portion 121 b. The terminals 121 are made of, for example,a conductor such as a metal. The inner portion 121 a of each terminal121 and a terminal of the photo device 110 are connected by a bondingwire 140 such as a fine metal line. The outer portion 121 b of theterminal 121 is a portion to be mounted on a wiring board via, forexample, solder and thus used to connect another device. Another deviceand the photo device 110 are electrically connected via the terminals121 and the bonding wires 140. The substrate 120 and the terminals 121form a connection member used to support the photo device 110 andelectrically connect the photo device 110 to another device.

The photo device 110, the inner portions 121 a of the terminals 121, andthe upper surfaces of the substrate 120 are covered with a transparentsealing member 160. A transparent plate 150 configured to cover andprotect the photo device 110 is arranged on the sealing member 160. Theside surfaces of the substrate 120, the side surfaces of the sealingmember 160, and the side surfaces of the transparent plate 150 are flushwith each other. The transparent plate 150 is made of, for example,glass. The sealing member 160 is made of, for example, a resin.

An example of a method of manufacturing an optical apparatus 100 will bedescribed next with reference to FIGS. 2A to 2F. FIGS. 2A to 2F areschematic sectional views showing steps in the manufacture of theoptical apparatus 100. First, as shown in FIG. 2A, a photo device 110and a substrate 200 having terminals 121 are prepared. In this step, aplurality of photo devices 110 may be prepared. For example, the photodevices 110 are prepared by manufacturing them from a silicon wafer by asemiconductor process and dividing the wafer by dicing. The terminals121 may be arranged in the substrate 200 in correspondence with each ofthe plurality of photo devices 110. The plurality of terminals 121 arearranged in, for example, a matrix in the substrate 200.

If the substrate 200 has a large size, unevenness of the distancebetween the photo device 110 and a transparent plate 230 (to bedescribed later) becomes large when arranging the transparent plate 230.On the other hand, if the substrate 200 has a small size, the number ofoptical apparatuses 100 manufactured from one substrate decreases,resulting in an increase in cost. To prevent these, the length of eachside of the upper surface of the substrate 200 prepared in this step maybe 100 mm (inclusive) to 200 mm (inclusive).

After that, as shown in FIG. 2B, each photo device 110 is arranged onthe substrate 200 while inserting an adhesive 131 between them. Forexample, the adhesive 131 is applied onto the substrate 200 using adispense method, printing method, or the like. The photo device 110conveyed by a collet 210 is placed on it.

As shown in FIG. 2C, the liquid adhesive 131 is cured to form a solidbonding member 130, thereby fixing the photo device 110 on the substrate200. For example, when the adhesive 131 is a thermosetting resin, theadhesive 131 is heated using an oven, a reflow furnace, or the like, andcured. The thickness of the bonding member 130 is, for example, 10 to 30μm. The thickness of the adhesive 131 to be applied is set inconsideration of its cure shrinkage ratio when forming the bondingmember 130. The linear expansion coefficient of the bonding member 130is, for example, 40 to 400 ppm/° C., and for example, 150 ppm/° C.

After that, as shown in FIG. 2C, the terminals of each photo device 110and inner portions 121 a of the terminals 121 are connected by bondingwires 140. When a sealing member 160 is a resin, a gold wire may be usedas the bonding wire 140. In this case, the bonding wires 140 can beprevented from being corroded by the resin. Flip chip connection may beused instead of connection by the bonding wires 140.

After that, as shown in FIG. 2D, a resin 220 for temporary fixing isformed near the edge of the upper surface of the substrate 200. Thetransparent plate 230 is arranged on the resin 220 and temporarilyfixed. The viscosity of the resin 220 is set to 500 mPa·s so as tomaintain the spacing between the substrate 200 and the transparent plate230. The transparent plate 230 forms a surface serving as the lightincident surface of the optical apparatus 100. When the transparentplate 230 is prepared in advance, the flatness of the light incidentsurface of the optical apparatus 100 can be improved. Antireflectionfinish such as AR coating may be applied to one surface of thetransparent plate 230 to improve the sensitivity of the photo device110. Next, the space between the substrate 200 and the transparent plate230 is filled with a liquid sealant 161. FIG. 2D shows a state in whichthe sealant 161 is injected halfway between the substrate 200 and thetransparent plate 230. The sealant 161 fills the space between thesubstrate 200 and the transparent plate 230 while contacting thesubstrate 200, the photo devices 110, and the transparent plate 230.

After that, as shown in FIG. 2E, the sealant 161 injected between thesubstrate 200 and the transparent plate 230 is cured, thereby formingthe solid sealing member 160. When the photo device 110 is an autofocussensor for a camera, a material having a transmittance of 90% or more inthe visible light range may be used as the sealing member 160. From theviewpoint of optical characteristics, a resin having a high transparencyand containing no filler is used as the sealing member 160. The sealant161 is, for example, a thermosetting resin or a photo-curing resin suchas an ultraviolet (UV) curing resin. Thermosetting may cause thermalexpansion of the transparent plate 230 and the substrate 200 andincrease the possibility of disconnection of the bonding wires 140.Hence, photo-curing may be used to cure the sealant 161. Whenphoto-curing is used, the sealant can be cured at a low temperature evenif it is heated to some extent after temporary curing. This can suppressthermal expansion of the constituent members. When a material thatpasses UV rays and the like for photo-curing is selected as thetransparent plate 230, the sealant 161 can be cured via the transparentplate 230. In the above-described example, the sealant 161 is injectedafter the transparent plate 230 is arranged. However, the transparentplate 230 may be placed after the sealant 161 is applied. However, tosuppress mixing of bubbles and foreign substances and increase theparallelism and spacing formation accuracy between the substrate 200 andthe transparent plate 230, the sealant 161 may be injected after thetransparent plate 230 is placed.

After that, as shown in FIG. 2F, the substrate 200, the sealing member160, and the transparent plate 230 are cut for each photo device 110using a dicing blade 240, thereby manufacturing the plurality of dividedoptical apparatuses 100. Individual portions of the substrate 200 aftercutting become substrates 120 of the optical apparatuses 100. Individualportions of the transparent plate 230 after cutting become transparentplates 150 of the optical apparatuses 100.

Factors that warp the transparent plate 150 of the optical apparatus 100will be described next with reference to FIGS. 3A and 3B. In the opticalapparatus 100 shown in FIG. 3A, the photo device 110 and the substrate120 warp upward due to a force acting between the photo device 110 andthe substrate 120. That is, warping occurs so that the portion near thecenter where the photo device 110 is arranged projects upward. As aresult, the transparent plate 150 warps upward as well. The force actingbetween the photo device 110 and the substrate 120 is generated by, forexample, the difference between the linear expansion coefficient of thephoto device 110 and that of the substrate 120. For example, assume thatthe photo device 110 and the substrate 120 both in an expanded state arebonded and then cooled. In this case, since the contraction ratio of thephoto device 110 and that of the substrate 120 are different, thesubstance having the larger linear expansion coefficient largelycontracts and warps so as to project toward the substance having thesmaller linear expansion coefficient. This is a so-called bimetaleffect.

In the optical apparatus 100 shown in FIG. 3B, a force generated byvolume shrinkage caused by the curing of the sealant 161 warps thetransparent plate 150 upward and the photo device 110 and the substrate120 downward. The optical apparatus 100 according to various embodimentsfor suppressing the warping of the transparent plate 150 caused by thesefactors and a method of manufacturing the same will be described below.According to the following embodiment, the magnitude of warping per mmcan be 2 μm or less in a direction along the major surface of the photodevice 110. If this condition is not satisfied, the magnitude of warpingper 10 mm exceeds 20 μm, for example, in the direction along the majorsurface of the photo device 110. This can greatly deteriorate theperformance of the optical apparatus 100.

In some embodiments, the bonding member 130 having a small elasticmodulus is used. In the following description, the elastic modulus isdefined by a Young's modulus. The unit of an elastic modulus representedby a Young's modulus is Pa, which means that the smaller the number is,the easier the material can deform. The elastic modulus (Young'smodulus) can be obtained by measuring the flexure of a member (testpiece) made of the same material as the bonding member 130 used in theactual optical apparatus 100. Note that the unit of a shear modulus isPa as well. However, all numerical values described as elastic moduli inthe following description are Young's moduli. Since the elastic modulusof the bonding member 130 is small, the force generated by thedifference between the linear expansion coefficient of the photo device110 and that of the substrate 200 can be absorbed by the deformation ofthe bonding member 130, and warping of the transparent plate 150 can besuppressed. In some embodiments, the bonding member 130 having anelastic modulus of 1 GPa or less is used. When the bonding member 130having an elastic modulus more than 1 GPa is used, the magnitude ofwarping per 1 mm in the photo device 110 can hardly be 2 μm or less, asdescribed above. When a bonding member having an elastic modulus of 2GPa is used for the sake of comparison in place of the bonding member130 according to this embodiment, an obvious deterioration is observedin the performance of the optical apparatus 100. The elastic modulus ofthe bonding member 130 may be 0.5 GPa or less (for example, 500 MPa orless). For example, an example of the adhesive 131 that becomes thebonding member 130 after curing is a bismaleimide resin in which afiller of PTFE (polytetrafluoroethylene) is dispersed within the rangeof 35 wt % (inclusive) to 45 wt % (inclusive). In this case, the elasticmodulus of the bonding member 130 is 300 MPa. Even when an epoxy resin,acrylic resin, polyethylene resin, or silicone resin is used, theelastic modulus of the bonding member 130 can be set to 1 GPa or less.However, the material or amount of a filler may be adjusted to set theelastic modulus of the resins described here to 1 GPa or less. Forexample, the elastic modulus of the epoxy resin or acrylic resin can beset to 2 to 3 GPa or 1 GPa or less by adjusting the material or amountof the filler. This also applies to the other resin materials. Thefiller may be a resin. A resin paste containing a metal filler such asAg (silver) can hardly have an elastic modulus of 1 GPa or less. Whenthe elastic modulus of the bonding member 130 is too low, the positionof the photo device 110 shifts at a high possibility when curing thesealant 161 shown in FIG. 2E. To prevent this, in some embodiments, thebonding member 130 having an elastic modulus of 0.05 GPa or more isused. The elastic modulus of the bonding member 130 may be 0.1 GPa ormore (for example, 100 MPa or more).

In some embodiments, the adhesive 131 having a low curing temperature isused. When the adhesive 131 that cures at a low temperature is used, thesubstrate 200 and the photo device 110 can be bonded in a state in whichtheir expansion amounts are small. Hence, the force generated betweenthe substrate 200 and the photo device 110 after cooling also becomessmall. The curing temperature of the adhesive 131 may be equal to orless than the glass-transition point of the substrate 200. The adhesive131 may be cured at a temperature equal to or less than theglass-transition point of the substrate 200. A typical material used forthe substrate 200 increases the linear expansion coefficient along withan increase in the temperature. As compared to a linear expansioncoefficient (α1) in a temperature range equal to or less than aglass-transition point Tg, a linear expansion coefficient (α2) in atemperature range more than the glass-transition point has a higherdegree (slope) of increase of the linear expansion coefficient withrespect to the temperature. For this reason, when the temperatureexceeds the glass-transition point of the substrate 200 upon heating forcuring the adhesive 131, the linear expansion coefficient of thesubstrate 200 increases largely, for example, to four to five timeslarger than in heating to a temperature equal to or less than theglass-transition point. As a result, the substrate 200 that is largelyexpanded is bonded to the photo device 110. A large force acts aftercooling, and the substrate 200 largely warps. This phenomenon isconspicuous when the material of the substrate 200 is a resin. Since theglass-transition point of the resin substrate used for the opticalapparatus 100 is, for example, 150° C. to 180° C., the adhesive 131having a curing temperature of, for example, 80° C. (inclusive) to 150°C. (inclusive) is used. The curing temperature of the adhesive 131 canbe lower than the glass-transition point of the bonding member 130obtained by curing the adhesive 131 but may be higher. This is becausethe elastic modulus of the bonding member 130 is 1 GPa or less, and evenin a temperature range higher than the glass-transition point of thebonding member 130, the influence of thermal expansion of the bondingmember 130 can be reduced. The glass-transition point of the adhesive131 may be room temperature or less or 0° C. or less. The adhesive 131containing the above-described bismaleimide resin has a glass-transitionpoint of about −30° C.

In some embodiments, the thin photo device 110 is prepared in the stepof FIG. 2A. As the thickness of the photo device 110, for example, anaverage of the thicknesses of a plurality of portions is employed. Theplurality of portions are, for example, portions corresponding to 3×3=9intersections between three vertical lines and three horizontal lines,which equally divide the vertical and horizontal sizes into four parts.This also applies to the thicknesses of other components to be describedbelow.

As shown in FIG. 1, a portion that covers the photo device 110 out ofthe sealing member 160 will be referred to as a first portion 160 a, anda portion other than the first portion 160 a of the sealing member 160will be referred to as a second portion 160 b. The second portion 160 bcovers the upper surfaces of the substrate 120 and the inner portions121 a of the terminals 121. When the upper surface of the photo device110 is rectangular, the first portion 160 a forms a rectangular column,and the second portion 160 b forms a rectangular tube. As shown in FIG.1, let h1 be the thickness of the first portion 160 a, and h2 be thethickness of the second portion 160 b.

The smaller the difference between the thickness h1 of the first portion160 a and the thickness h2 of the second portion 160 b is, the smallerthe difference between the amount of shrinkage of the first portion 160a and that of the second portion 160 b caused by curing of the sealingmember 160 is. As a result, warping of the transparent plate 150 causedby a force generated with respect to the photo device 110 as the fulcrumbecomes small. Hence, use of the thin photo device 110 makes it possibleto reduce the difference between the thicknesses h1 and h2 and suppresswarping of the transparent plate 150. On the other hand, if the photodevice 110 is too thin, the difficulty in processing the photo device110 increases, and the yield lowers. Hence, in the step of FIG. 2A, thephoto device 110 having a thickness of, for example, 0.2 mm (inclusive)to 0.3 mm (inclusive) is prepared. The typical photo device 110 is madeof a plurality of materials having different linear expansioncoefficients. However, the linear expansion coefficient of the photodevice 110 can be approximated by the linear expansion coefficient of amaterial that occupies 50% or more of the volume of the photo device110. For example, in the photo device 110 including a 0.01-mm thicksilicon oxide film and a 0.01-mm thick resin film formed on a 0.2-mmthick silicon substrate, the linear expansion coefficient of silicon canbe regarded as the linear expansion coefficient of the photo device 110.

In some embodiments, to suppress warping of the transparent plate 150caused by the shrinkage amount difference between the first portion 160a and the second portion 160 b of the sealing member 160, the width ofthe second portion 160 b of the sealing member 160 is narrowed. This canweaken the force received by the transparent plate 150 due to shrinkageof the second portion 160 b and suppress warping of the transparentplate 150. The width of the second portion 160 b corresponds to thedistance from the edge of the photo device 110 to the edge of thesubstrate 120. The width of the second portion 160 b is set to 2.5 mm orless. To do this, the photo devices 110 are arranged at an interval of5.0 mm or less. If the width of the second portion 160 b is too narrow,the interval between the adjacent photo devices 110 becomes narrow, thespace between the photo devices 110 cannot sufficiently be filled withthe sealant 161, and a gap may be formed in the step of FIG. 2D. Thislowers the strength of the optical apparatus 100. To prevent this, theinterval between the photo devices 110 may be set to 0.5 mm or more. Thespace having a width of 0.5 mm formed between the photo devices 110 issufficiently wide to form the bonding wires 140. When the photo devices110 are cut at the midpoint between them, the width of the secondportion 160 b is 0.25 mm or more. That is, in some embodiments, thephoto devices 110 are arranged on the substrate 200 at an interval of0.50 to 5.0 mm in the step of FIG. 2B. When cutting is performed in thestep of FIG. 2F, the width of the second portion 160 b is 0.25 mm(inclusive) to 2.5 mm (inclusive). For example, when the long side ofthe upper surface of the photo device 110 hash a length of 5 to 20 mm,and the short side has a length of 2.5 to 10 mm, the above-describedarrangement and cutting are done such that the long side of the uppersurface of the substrate 120 has a length of 6 mm to 30 mm, and theshort side has a length of 3.5 to 30 mm. More specifically, when thelong side of the upper surface of the photo device 110 has a length of11.6 mm, and the short side has a length of 6.4 mm, the above-describedarrangement and cutting may be done such that the long side of the uppersurface of the substrate 120 has a length of 13.6 mm, and the short sidehas a length of 9.3 mm.

In some embodiments, the substrate 200 having a low rigidity (i.e.stiffness) is prepared in the step of FIG. 2A. The lower the rigidity ofthe substrate 200 is, the smaller the warping of the transparent plate150 caused by warping of the substrate 200 is. In addition, when therigidity of the substrate 200 is low, a force generated by volumeshrinkage of the sealing member 160 is absorbed by deformation of thesubstrate 200, and a force applied to the transparent plate 150 can besuppressed. Generally, the rigidity of an object is known to be given by(elastic modulus of object)×(thickness of object)³. In some embodiments,letting Es (GPa) be the elastic modulus of the substrate 200, and Ts(mm) be the thickness of the substrate 200, the substrate 200 satisfying(Es)×(Ts)³≦2.5 is prepared in the step of FIG. 2A. If the substrate 200is too thin, the workability degrades, and the yield lowers. Thesubstrate 200 having a thickness of 0.2 mm or more may be prepared. Forexample, the substrate 200 formed from a glass epoxy or BT resin havingan elastic modulus of 20 to 40 GPa and having a thickness of 0.3 to 0.5mm is prepared.

In some embodiments, the substrate 200 having a small linear expansioncoefficient is prepared in the step of FIG. 2A. As described withreference to FIG. 3A, warping of the photo device 110 and the substrate200 is derived from the difference between the linear expansioncoefficient of the photo device 110 and that of the substrate 200. Thelinear expansion coefficient of the photo device 110 is, for example, 1to 5 ppm/° C. When the material of the photo device 110 is silicon, thelinear expansion coefficient is 2.6 ppm/° C. When the linear expansioncoefficient of the substrate 200 is made close to that of the photodevice 110, warping of the transparent plate 150 can be suppressed. Thelinear expansion coefficient of the substrate 200 may be larger thanthat of the photo device 110. As the material of the substrate 200, aresin having a linear expansion coefficient of 5 to 50 ppm/° C. isusable. In some embodiments, a resin having a linear expansioncoefficient of 20 ppm/° C. is used as the material of the substrate 200.In some embodiments, a resin having a linear expansion coefficient of 15ppm/° C. is used as the material of the substrate 200.

In some embodiments, the transparent plate 230 having a high rigidity(i.e. stiffness) is prepared in the step of FIG. 2D. In someembodiments, a material having a high elastic modulus is used as thetransparent plate 230. This can suppress warping of the transparentplate 230. The elastic modulus of the transparent plate 230 may behigher than that of the substrate 200. This makes it possible to causethe substrate 200 that readily deforms as compared to the transparentplate 230 having a light incident surface to absorb the internal stressof the optical apparatus 100 and suppress warping of the light incidentsurface. For example, letting Et (GPa) be the elastic modulus of thetransparent plate 230, and Tt (mm) be the thickness of the transparentplate 230, a material satisfying (Et)×(Tt)³≧9 is used. Therefore, thetransparent plate 230 may have a higher rigidity than the substrate 200,and (Es)×(Ts)³<(Et)×(Tt)³ may be satisfied. Examples of the material areborosilicate glass, IR-cut glass, quartz, and lithium niobate. Forexample, a borosilicate glass plate having a thickness of 0.5 mm has anelastic modulus of 70 GPa. When the transparent plate 230 is thick, thesize of the optical apparatus 100 is large. Hence, the thickness of thetransparent plate 230 is set to 1.5 mm or less. In addition, the linearexpansion coefficient of the transparent plate 230 can be 1 to 10 ppm/°C., for example, 3.8 ppm/° C. When the substrate 200 which has a higherlinear expansion coefficient than that of the transparent plate 230 andthe photo device 110 is used, using the bonding member 130 having theelastic modulus of 1 GPa or less shows significant decrease of a warpingof the substrate 200.

In some embodiments, the elastic modulus of the sealing member 160 is0.01 GPa or less. Employing such a soft sealing member 160 is effectivein relaxing the stress between the transparent plate 230 and thesubstrate 200. In some embodiments, the cure shrinkage ratio of thesealing member 160 is 2% (inclusive) to 5% (inclusive). The linearexpansion coefficient of the sealing member 160 may be 80 to 320 ppm/°C., for example, 168 ppm/° C.

In some embodiments, the sealing member 160 is a UV curing resin. Thiscan suppress warping caused by the expansion coefficient differencebetween the substrate 200 and the transparent plate 230 upon heating. Toprevent the sealing member 160 from being distorted by abrupt curingshrinkage at the time of UV curing, weak UV irradiation of 200 mJ orless may be performed first, and strong UV irradiation may then beperformed.

As described above, when at least one of the above-described methods isemployed, and the above-described at least one condition is satisfied,warping of the transparent plate 150 of the optical apparatus 100 can besuppressed. For example, when the photo device 110 is an autofocussensor, it is possible to suppress the positional shift of thephotodiode in the photo device 110 and improve the distance measurementaccuracy by suppressing warping of the transparent plate 150. Forexample, When the photo device 110 is a photo device (image sensor) forimage capturing, it is possible to obtain a high quality image withsmall distortion by suppressing warping of the transparent plate 150.

While the present invention has been described with reference toexemplary embodiments, it is to be understood that the invention is notlimited to the disclosed exemplary embodiments. The scope of thefollowing claims is to be accorded the broadest interpretation so as toencompass all such modifications and equivalent structures andfunctions.

This application claims the benefit of Japanese Patent Application No.2013-171712, filed Aug. 21, 2013, which is hereby incorporated byreference herein in its entirety.

What is claimed is:
 1. A method of manufacturing an optical apparatus,comprising: arranging a photo device above a substrate with an adhesivelocated between the photo device and the substrate; forming a bondingmember that bonds the substrate and the photo device by curing theadhesive after the arranging of the photo device; arranging, above thephoto device, a transparent plate and a sealant, the sealant coveringthe photo device and being located between the transparent plate and thesubstrate in contact with the transparent plate and the substrate; andforming a sealing member by curing the sealant after the arranging ofthe transparent plate and the sealant, wherein an elastic modulus of thebonding member is 1 GPa or less, and wherein the forming of the sealingmember includes a first ultraviolet irradiation to the sealant and asecond ultraviolet irradiation to the sealant after the firstultraviolet irradiation, and the second ultraviolet irradiation isstronger than the first ultraviolet irradiation.
 2. The method accordingto claim 1, wherein an elastic modulus of the transparent plate ishigher than that of the substrate.
 3. The method according to claim 1,wherein a linear expansion coefficient of the transparent plate ishigher than that of the substrate and the photo device, and the elasticmodulus of the bonding member is from 0.1 GPa to 1 GPa.
 4. The methodaccording to claim 1, wherein in the arranging the transparent plate andthe sealant, after the transparent plate is arranged above the photodevice, the sealant is injected between the transparent plate and thesubstrate.
 5. The method according to claim 1, wherein letting Ts (mm)be a thickness of the substrate and Es (GPa) be an elastic modulus ofthe substrate, and letting Tt (mm) be a thickness of the transparentplate and Et (GPa) be an elastic modulus of the transparent plate,(Es)×(Ts)³<(Et)×(Tt)³ is satisfied.
 6. The method according to claim 1,wherein letting Ts (mm) be a thickness of the substrate and Es (GPa) bean elastic modulus of the substrate, (Es)×(Ts)³≦2.5 is satisfied.
 7. Themethod according to claim 1, wherein letting Tt (mm) be a thickness ofthe transparent plate and Et (GPa) be an elastic modulus of thetransparent plate, (Et)×(Tt)³≧9 is satisfied.
 8. The method according toclaim 3, wherein the adhesive has thermosetting properties, and a curingtemperature of the adhesive is not more than a glass-transition point ofthe substrate.
 9. The method according to claim 1, wherein a cureshrinkage ratio of the sealing member is from 2% to 5%.
 10. The methodaccording to claim 1, wherein a linear expansion coefficient of thesubstrate is 20 ppm/° C. or less.
 11. The method according to claim 2,wherein the elastic modulus of the bonding member is from 0.05 GPa to0.5 GPa.
 12. The method according to claim 11, wherein at least one of(a)-(c) is satisfied: (a) a thickness of the photo device is from 0.2 mmto 0.3 mm, (b) the thickness of the transparent plate is 1.5 mm or less,and (c) the thickness of the substrate is 0.2 mm or more.
 13. The methodaccording to claim 1, wherein the photo device is an autofocus sensor.14. The method according to claim 1, wherein in the arranging the photodevice, a plurality of photo devices are arranged above the substrate,and the method further comprises cutting the substrate, the transparentplate, and the sealing member for each of the plurality of photodevices.
 15. The method according to claim 14, wherein a length of eachside of the substrate before cutting is 200 mm or less.
 16. The methodaccording to claim 14, wherein in the cutting, the substrate is cut at aposition having a distance from an edge of the photo device of 0.25 mmto 2.5 mm.
 17. The method according to claim 1, wherein the adhesivecomprises a bismaleimide resin in which a filler ofpolytetrafluoroethylene is dispersed within a range of 35 wt % to 45 wt%.
 18. The method according to claim 1, wherein the sealant is cured byphoto-curing via the transparent plate.
 19. The method according toclaim 1, wherein the sealant is an ultraviolet curing resin.